Lake Superior Surface Water Temperatures Up 2.5C Since 1979 - 2X Atmospheric Warming Rate

[hatrack]

MINNEAPOLIS, March 22 U.S. scientists have determined Lake Superior's summer surface temperatures have increased by approximately 2.5 degrees Celsius since 1979.

The researchers, led by Jay Austin and Steven Colman of the University of Minnesota, said the increase is about twice the rate of regional atmospheric warming.

Austin and Colman hypothesize declining winter ice cover is causing the lake to absorb more solar radiation than during past years. That increased absorption causes earlier stratification of the lake at a rate of roughly half a day per year.

Large mid-latitude lakes often freeze in winter, mix thoroughly during spring and fall, and stratify in summer due to solar heating. Austin and Colman said the earlier start to Lake Superior's stratified season significantly increases the period during which the lake warms, resulting in higher summer temperatures.

EDIT

http://www.earthtimes.org/articles/show/42989.html

[ben_meyers]

1. What is the significance of this?

In a previous thread I asked for help answering my granddaughters question about the great lakes.
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x86982
Mostly I got links or was told to watch Al Gore's movie. We did watch the movie, and I followed the links but Her question remains, mainly how do we explain that 15000 years ago the Great Lakes were under large sheets of ice, 8500 years ago the area was dry and had a large cedar forest and now is under 50 feet or so of water?

The question? How does all this happen without human intervention.

[Javaman]

2. The higher the temp, usually means, a lower oxygen level, which means...

more dead fish.